/*
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at 
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *  
 */

using System;
using java = biz.ritter.javapi;

namespace org.apache.commons.collections
{

    /**
     * Defines a functor interface implemented by classes that perform a predicate
     * test on an object.
     * <p>
     * A <code>Predicate</code> is the object equivalent of an <code>if</code> statement.
     * It uses the input object to return a true or false value, and is often used in
     * validation or filtering.
     * <p>
     * Standard implementations of common predicates are provided by
     * {@link PredicateUtils}. These include true, false, instanceof, equals, and,
     * or, not, method invokation and null testing.
     * 
     * @since Commons Collections 1.0
     * @version $Revision$ $Date$
     * 
     * @author James Strachan
     * @author Stephen Colebourne
     */
    public interface Predicate
    {

        /**
         * Use the specified parameter to perform a test that returns true or false.
         *
         * @param object  the object to evaluate, should not be changed
         * @return true or false
         * @throws ClassCastException (runtime) if the input is the wrong class
         * @throws IllegalArgumentException (runtime) if the input is invalid
         * @throws FunctorException (runtime) if the predicate encounters a problem
         */
        bool evaluate(Object obj);

    }
}
